Trip valve for use with the air brakes of railway vehicles



May 11 1926.

A. D. JENKINS ET AL TRIP VALVE FOR USE WITH THE AIR BRAKES 0F RAILWAY VEHICLES Filed August. 29, 1924 2 Sheets-Shut 1 .ZZdnTar-S JZ'D. zfqnzfz nfi Z5: 7:570:71: wapaviakom rz'ilain; W

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May 11 1926. 1,584,299

A. D. JENKINS ET AL TRIP VALVE FOR USE WITH THE AIR BRAKES 0F RAILWAY VEHICLES 7 Filed August 29' 1924 1 2 Sheets-Sheet 2 fnueniars Jami-(1'05 if 'Z'Broo/Q W 6, Davidson,

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Patented May 11, 1926 UNITED stares A isstzaa Mme. OEQFEQEQ ARTHUR DAVID JENKINS, ERNEST TELFORD BROOK, WILLIAM SHERBIFFS DAVIDSON, AND PERCIVAL FREDERIC BRITTAIN, LONDGN, ENGLAND.

TRIP VALVE FOR USE WITH THE AIR BRAKES or RAILWAY VEHICLES.

Application filed August 29, 1924.

This invention refers to improvements in or relating to trip valves for use with the air brakes of railway vehicles.

The primary object 01" the present inven tion is to improve and simplify the construction and arrangement of the valve; to eliminate leakage of air, and reduce the friction oi": the working parts ILO a minimum, and to render the valve more positive and reliable in operation.

According to the present invention we provide an automatic trip valve for use with the air brakes of railway vehicles, comprising a casing divided by a transverse web into an upper valve chamber in communication with the brake pipe and a lower chamber having, a controlled exit to the atmosphere, a valve stem arranged in said casing, adisc valve at the upper end of the stem co-operating with a seating in the upper valve chamber and adapted when the valve is tripped by the operating mechanism to admit air under pressure from the upper chamber to the lower chamber, a second disc valve or battle on the said valve stem adapted to cooperate by means of its periphery with a surrounding annulus or seating in such a manner that upon the initial operation of the first valve the air admitted to the lower chamber will act upon the valve disc or battle and complete the opening operation of the first valve and simultaneously put the said lower chamber into communication with the atmosphere, and a re-setting lever engaging said valve spindle intermediate its length.

In order that the present invention may be clearly understood and more readily carried into effect, it is hereinafter described with reference to the accompanying drawings, in which Figure 1 is a sectional side elevation of a trip valve constructed in accordance with the present invention and showing the valve and other parts in the position they assume when the valve is closed, but omitting the cam lever or other trip mechanism for operating the valve stem;

Figure 2 is a corresponding end elevation of said valve, and

Figure 3 is a sectional plan view thereof.

Fig. d is a sectional View showing the improved trip valve as constructed for use in connection with vacuum brakes.

As shown and according to the present in- Serial No. 73%,979.

veution the improved trip valve comprises a substantially cylindrical body portion or casting; ('1, having an upper screw-threaded extension cap or plug 6, a lower disc or closure plate 0 carrying a bushing c for the valve spindle and detachably secured thereto by bolts or the like (Z, and an inlet connection '0 to which thebrake pipe f is screwed. The body portion of the cylinder 64 is divided by means of a transverse web 9 into an upper valve chamber h communicating with the brake pipe f and a two-part lower chamher 2', 7' connected by means of a port 70. The aforesaid two-part chamber 71, j is so constituted by means of a second transverse web Zwhich is centrally perforated and provided with a bush m through which slides the central operating spindle not the valve 0. The said valve spindle n carries at its upper end the aforesaid starting valve 0 which is provided with a leather or like washer 39 cooperating with a seating 9 formed by the web This valve 0 and its washer 7? are adapted to be secured in place on the reduced upper end of the valve spindle 0 between a lower metal washer 1" and a pair of lock nuts 8. At or about the middle of its length the valve spindle it carries a further valve disc or battle 2 which when the valve 0 is closed assumes the position shown in the drawings, practically closing the chamber 2', 7', but when the valve 0 is tripped air from the brake pipe 7' rushes in past the valve 0, enters the chamber 2', j, and, passing through the port 70, raises the aforesaid disc or battle 2? and escapes into the air by way of the exhaust port a and chamber or box 1). The lower valve disc or battle tis also secured on a reduced portion onthemain spindle n by means of a suitable lock nut w, and by reason of the fact that no friction takes place between this valve disc or baflie t and its surrounding annulus or seating 06, the said disc or baflie 6 may conveniently be constructed of metal or other rigid material and does not require to be accurately machined orfitted. Arranged in conjunction with the trip cock is a bell crank lever 3 which is fulcrumed at a to the body of the valve casing a in such a manner that its lower or short end projects through the port to into the exhaust chamber or box o where it is provided with a disc-shaped end 10 adapted to enter a transverse slot 11 formed in the body of the valve spindle n. The upper end of the bell crank lever y is provided with a perforated eye 12, to which a suitable connection may be made whereby the valve 0 may be readily re-set, after it, is operated. The bell crank lever 7 is conveniently held in position on the horizontal fulcrum or pin a between a suitable packing washer 13 and a helical spring 14 interposed between the boss of the bell crank lever and the side brackets 15, 16 supporting the fulcrum pin 2.

It will be seen from the construction described and shown in the drawings that the whole of the parts are readily accessible and that the valve spindle can be removed as a whole by first removing'the cap or plug 1) and the valve 0 and then withdrawing the said valve spindle from the lower end of the casing after the plate or disc has been removed.

It will also be seen that by the present invention no gland-tight joint for the Valve spindle is required on the pressure side of the apparatus, thus considerably reducing the friction and minimizing the leakage of air.

The valve stem itself may conveniently be moved by means of a cam lever hanging in such a position that it can be turned on its pivot by a tappet or arm set by the signal. The cam lever may if desired be arranged to actuate the valve whichever be the direction in which the vehicle is travelling, or it may only actuate the vehicle when it is travelling in one direction, and not in the other direction.

It will be obvious that the improved trip valve previously described may be used for vacuum brakes as well as with air brakes of the Westinghouse type. In the latter arrangement the disc valve 10 at the upper end of the stem at and also the second disc valve or battle t on the stem would be suitably arranged; that is to say, the valve at the upper end of the stem would co-operate with a seating 9' arranged in the lower valve chamber, and the valve stem itself would move down instead of up. In this arrangement the upper chamber could be. dispensed with and its place would be taken by a socket piece adapted to be connected directly to the brake pipe f. This construction is illustrated particularly in Fig. 4.

What we claim is 1. An automatic trip valve for use with the compressed air brakes of railway vehicles, comprising a casing divided by a transverse web into an upper valve chamber in communication with the brake pipe and a lower chamber having a controlled eXit to the atmosphere,a valve stem arranged in said casing, a disc valve at the upper end of the stem co-operating with a seating in the upper valve chamber and adapted when the valve is tripped by the operating mechanism to admit air under pressure from the upper chamber to the lower chamber, a second disc valve or baflle on the said valve stem adapted to co-operate by means of its periphery fitting in a non-sealing relation within a surrounding annulus in such a manner that upon the initial operation of the first valve the air admitted'to the lower chamber will act upon the valve disc or baille and complete the opening operation of the first valve and simultaneously put the said lower chamber into communication with the atmosphere, and a resetting lever engaging said valve spindle intermediate its length.

2. An automatic trip valve according to the claim 1, for use with the air brakes of railway vehicles in which only the one opening valve is arranged on the pressure or vacuum side of the apparatus, so that the spindle does not have to be packed against air pressure, thus preventing leakage of air and reducing the friction on the working parts.

3. An automatic trip valve according to claim 1, in which the re-setting lever is also arranged on the atmosphere side of the valve.

In testimony whereof we have hereunto signed our names.

ARTHUR DAVID JENKINS.

ERNEST TELFORD BROOK.

WILLIAM SHERRIFFS DAVIDSON. PERCIVAL FREDERIC BRITTAIN. 

